The UK government has pre-ordered 30m dose of the jab, which has been trialled on a single dose regimen.
The news comes after Novovax reported results of its phase 3 vaccine trial on Friday morning, which showed it to be 89.3% effective. The UK has 60m doses of that vaccine on order.
Janssen’s global trial involved 43,783 participants, among whom 468 experienced symptomatic COVID-19. It found that the vaccine was 66% effective in preventing moderate or severe disease 28 days after receiving a single dose of the jab, however some protection was observed as early as day 14.
Different levels of protection against COVID-19 were observed in different countries involved in the trial. At 28 days post-immunisation the vaccine was found to be 72% effective in the United States, 66% effective in Latin America and 57% effective in South Africa.
Preventing severe disease
However, the trial found that overall the vaccine was 85% effective in preventing severe disease in all regions at 28 days post-vaccination. Efficacy against severe disease also increased over time, with no cases reported in participants from 49 days post-vaccination.
Janssen’s parent company Johnson & Johnson said that the vaccine had also ‘demonstrated complete protection against COVID-related hospitalisation and death, 28 days post-vaccination’. None of the participants who had the vaccine and caught the virus more than 28 days after they were vaccinated required medical intervention, the trial found.
No safety concerns were reported during the trial. The company is also conducting a parallel phase 3 trial, which involves UK participants, that is looking at the efficacy of a two-dose vaccine regimen.
Like the Oxford/AstraZeneca vaccine the Janssen jab is an adenoviral vector vaccine. It has been created using the same technology Janssen used to create an Ebola vaccine, which has been approved by the European Commission.
The vaccine can be stored for for two years at -20°C and three months at standard vaccine fridge temperatures of 2-8°C.
Paul Stoffels, chief scientific officer at Johnson & Johnson said: ‘These topline results with a single-shot COVID-19 vaccine candidate represent a promising moment. The potential to significantly reduce the burden of severe disease, by providing an effective and well-tolerated vaccine with just one immunisation, is a critical component of the global public health response.’
The company said it intends to apply for emergency use authorisation in the US in early February.
The UK vaccine portfolio
Approved by MHRA
- Pfizer/BioNTech – 40m doses
- Oxford/AstraZeneca – 100m doses
- Moderna – 17m doses (first doses due to be delivered to the UK in April/May)
In clinical trials
- Novavax – Phase 3 – 60m doses
- Janssen – Phase 3 – 30m doses
- GSK/Sanofi – Phase 1/2 – 60m doses
- Valneva – Phase 1/ 2 – 60m doses secured, with an option to acquire a further 130m if the vaccine is approved by the MHRA